David: Can you tell us what it is you do? Because I know you do quite a number of things.

SG: Well, in the sciences, I’m interested in understanding how diversity emerges in infectious disease systems.

David: You’re not just a scientist though, are you?

SG: No, I write novels as well.

David: And how do those two things sit together in one brain?

SG: This is a question I’ve been asked a lot, and to me they come from very much the same source, which is a desire to understand or come to terms with the world, the universe.

David: So they’re not different kinds of thinking for you? Because people often imagine that scientific thinking is very different to a more literary or artistic thinking.

SG: At one level I think they are the same kind of thinking in that they’re driven by the same sort of desire to make sense of the internal and external universe that I happen to inhabit. But the languages employed are very different, I think.

In science, much of my pleasure in using words is that they adhere very closely to whatever concept I need them to represent. So I’m always seeking there to reduce the distance between the word and what it represents.

David: A sort of exactness?

SG: Yes. So you want them to… When I write, if I’m writing an equation and I use a symbol ‘x’, I really want its meaning to be precise. I feel like I’ve failed if ‘x’ means too many different things. So the closer ‘x’ is to what I want it to represent, the happier I am. Whereas when I’m writing fiction, I like there to be a gap between the word and what it refers to. I think a lot of the energy of fiction lies in that gap.

David: A sort of ambiguity?

SG: It’s a sort of disorder that’s not an arbitrary disorder. It’s somewhere… It’s moving away from order, but not so far as to be so ambiguous.

Ard: In science people often think that it’s all about cold hard facts and there’s no imagination. And then, obviously, writing novels is about imagination. What do you think about that dichotomy?

SG: Well, I think science is all about imagination. And what attracts me to science is the ability, or the opportunity, to be imaginative. So, for me, my journey through science has been one of using my imagination to come up with different ideas.

David: Is there a narrative in science? Does science use narrative, or is that purely…?

SG: I think narrative is a very strong element in science. I think…

David: Really?

SG: To me, narrative is where we’re headed.

David: That’s not obvious to a lot of people. I think in the popularisation of science, it’s a great big museum of facts. There’s a drawer with a fact here and then a drawer with another fact there, and he who had the largest number of drawers with facts in is the best! For you, it’s not like that? I mean, what’s the role…

SG: For me, it’s not like that.

David: …of narrative in science, then? I mean, how does it…?

SG: Because I’m interested in coming up with theories – I am a theoretical biologist at the end of the day – so theories are, of course, stories. So, for me, it’s not very interesting to just have a pile of facts.

There’s a huge synergy between actually arriving at the right narrative structure and the process of science as I experience it, which is recruiting these facts and then trying to think of a way in which they fit together that is coherent.

Ard: So sometimes the scientific facts fit together to tell a story, and the same is happening when you’re writing a novel?

SG: I don’t actually like the word story, myself. I think narrative is a better term.

Ard: Narrative. A real narrative. So would you say that what makes a scientific theory or narrative a good one, is that it’s fruitful? That it somehow goes on its own and does something that you didn’t even think it was going to do when you put it together?

SG: I’ve been searching for a long time for what does make a good narrative because it’s the same in fiction. At some point the book has, for me anyway, the right narrative.

David: It’s interesting what you said, though, because I’ve spent my professional life talking to scientists, and most often scientists will say, ‘In science, you should just stick to the facts.’

How often have you heard that from a scientist? ‘In science, we stick to the facts.’ Which would suggest that if I know these three facts, then I should only talk about them. I shouldn’t generate a story that suggests it might go somewhere, to use your phrase. And yet that is the strength of a theory, isn’t it? That it points to where you might go next?

SG: It points beyond facts. Exactly. I can’t think of any piece of science that’s been done that doesn’t take the facts and then construct from those facts something greater than the sum of the facts. But I was thinking in terms of it being fruitful.

David: What was it? Use and…

Ard: Usefulness and fruitfulness.

David: Tell me the difference.

SG: So, usefulness, I suppose… You know, many models, particularly in physics, have been ridiculously useful. And their validation in some ways is contained within their usefulness. The fact that they can send us to the moon is pretty useful. But then there are also fruitful theories. Fruitful, I think, is better than that. It’s not just useful: it’s creating a universe that will allow us to move forward.

Ard: I think fruitfulness is a hard thing to explain to an outsider, but you know it when you see it. A fruitful theory is something that explains something about the world that you see, so it’s important that it links to truth. But it also often tells you things that you didn’t know before, and then those things end up also being found in nature. And then it’s fruitful: it told you something you didn’t expect.

SG: It offers insights.

Ard: Insights, and often unexpected ones: ones that you wouldn’t have ever come up with had you not written the theory down.